Improvement in steering-propellers



F. G. FOWLER.

Steering Propellers. No. 143,896. Patented0ct.21,1&73.

- Wiingsses. I fie men 70% wwfiifi v M m,

U ITED STATES PATENT OFFICE.

FRANK G. FOWLER, OF BRIDGEPORT, CONNECTICUT.

IMPROVEMENT IN STEERLNG-PROPELLERS.

Specification forluil lg part of Letters Patent No. 143,S96,dated October 21, 1873; application filed November 22, 1870.

To all whom it may concern:

Be it known that I, FRANK G. FOWLER, of Bridgeport, in the county of Fairfield, State of Connecticut, have invented an Improvement in Steering-Propellers, of which the following is a specification:

My invention consists in so forming a steering-propeller blade that its pitchis varied according to the radial distance of different parts of its surface, and is made to operate with greater force on the outer edges than upon the edges nearest the shaft, thereby diminishing the strain on the arms of the eccentrics.

In the accompanying drawing, Figure l is a side view of my improved steering-propeller blade; Fig. 2, a sectional plan of the same,

and Fig. 3, a sectional plan of the propeller with improved blades.

The outer face of the blade, or that most remote from the shaft, is formed with a convex surface, the inner face being, by preference, concave. The manner in which these curved surfaces serve to equalize the effective force against the water will be understood by reference to Fig. 3.

Had these blades plane surfaces,'as in ordinary steering propellers, their whole surfaces would have the same angle, and consequently their outer edges, being farthest from the center of motion, would move most rapidly; but by reason of the curvature of the blades their outer extremities having the greatest motion have the finer angle, and their inner extremities having the least motion have the coarser angle. The difference in the velocities of the two extremities or edges of the blades being compensated for by a difference of angle, and

the curvature being such as to cause them to propel with equal force over their entire sur face. The curvature has the effect of relieving the eccentric arms of a great amoiuit of strain that would otherwise devolve upon them. The 

